The inspector general's report, issued earlier this month, ranked Oregon in the bottom quarter of states for Clean Water Act enforcement.

Incomplete federal data on Oregon's program contributed to that ranking. But a more recent report from the EPA's Seattle office put Oregon below national averages in both annual inspections of major polluters and in significant problems identified, two of the three performance indicators that the inspector general focused on.

Oregon's Department of Environmental Quality inspects 46 percent of the state's 68 major facilities annually and a quarter of the roughly 400 sewage plants and industries required to get individual Clean Water Act permits for water discharges, according to the more recent data.

Nationwide, state agencies inspect just under two-thirds of major facilities annually. The national goal for major facilities is 100 percent; there is no national goal for non-major plants.

Oregon also finds significant non-compliance with water quality rules in just under 3 percent of major facilities each year. The national average is about 24 percent.

DEQ officials say the disparities reflect the agency's focus on smaller sewage plants and industries, which experience shows have more problems than large plants.

The review out of EPA's Seattle office, issued in September, concluded that Oregon met EPA requirements for Clean Water Act inspections conducted, violations found and penalties issued, they note.

EPA's region 10, based in Seattle, agreed that Oregon should inspect all major facilities once every two years and all non-major plants once every 5 years, and the state is on track to do that, said Les Carlough, a DEQ senior policy advisor.

"We think we have often gotten the larger dischargers into compliance, and the sources of pollution are increasingly becoming these smaller dischargers," Carlough said. "Yet it's very difficult to get (the EPA's national office) to move beyond this old paradigm that's based on a permitting system for big dischargers."

The inspector general's report criticizes EPA's regional offices for uneven oversight of state programs that implement federal air, water and land pollution laws. Inconsistent state enforcement of environmental statutes "has been a persistent and widespread problem," the report says.

In 2005, Region 10 concluded that Oregon rivers are not adequately protected because of widespread deficiencies in the way state authorities regulated industrial sites and sewage plants. But state enforcement has improved since then, Lauris Davies, Region 10's associate director of compliance and enforcement, said this week.

In the most recent review, "We thought they were doing a good job across all three programs (water, air and land)," Davies said.

Environmental groups are skeptical. In June, Oregon's Environmental Quality Commission adopted the strictest standards for toxic water pollution in the United States. But budget cuts and wariness of political blowback hinders DEQ's aggressiveness in the field, said Brett VandenHeuvel, executive director of Columbia Riverkeeper.

"Fundamentally, there's a lack of resources and a lack of incentive," VandenHeuvel said. "The standards on paper mean nothing if there are few inspections and little enforcement."